This invention relates to an electric component unit, and more particularly to an electric component unit including a terminal fitment which permits connection of a connection conductor to an electric component without soldering.
Use of flon is subject to restriction in view of environmental pollution, so that it Is highly required to connect a terminal conductor, a lead wire or the like to a connection electrode on a circuit board without soldering.
U.S. Pat. No. 5,546,280 (corresponding to Japanese Patent Application No. 318669/1994) issued to the assignee discloses two kinds of soldering-less terminal connection structures each constructed so as to connect a core of a lead wire to a connection electrode on a circuit board without soldering.
Also, the U.S. patent discloses a connection structure including a terminal fitment integrally provided with a conductor holding section and an elastic contact terminal section. The terminal fitment is so constructed that the elastic contact terminal section connects the conductor holding section to an electrode on a circuit board without soldering. Further, the U.S. patent discloses a structure for connecting a plurality of electrodes on a circuit board and a plurality of connection conductors to each other without soldering.
In addition, Japanese Patent Application Laid-Open Publication No. 189316/1998 (Japanese Patent Application No. 350137/1996) discloses a soldering-less connection structure wherein a terminal assembly includes a terminal fitment provided with two conductor holding sections and a conductive coiled spring arranged between the terminal fitment and an electrode on a circuit board.
The conventional terminal fitments described above each include four holding elements (divided elements or edge sections) which cooperate with each other to interposedly hold the end of the connection conductor therebetween and bite at a distal end thereof into an end of the connection conductor when drawing force is applied to the connection conductor. The distal end of each of the holding elements is formed Into the same configuration while being inclined at substantially the same angle. The holding elements in each pair opposite to each other are so arranged that a distance between the distal ends is smaller than a diameter of the connection conductor. Thus, when the connection conductor is inserted through the terminal fitment, the four holding elements are forcedly enlarged to interposedly hold the end of the connection conductor together. Then, when drawing force is applied to the connection conductor, the four holding elements are caused to bite at an edge thereof Into the end of the connection conductor, to thereby keep the connection conductor from being released from the terminal fitment.
Unfortunately, in the conventional terminal fitment used for the electric component unit, it is required to concurrently enlarge the ends of the four holding elements when the connection conductor is inserted through the terminal fitment. Insertion of the connection conductor through the terminal fitment by manual operation Is deteriorated in workability when force applied to the connection conductor during the insertion is increased. Also, when insertion of the connection conductor Is carried out by means of an automatic inserting machine, it is required to adjust force for the insertion every time when the connection conductor is varied in diameter.
A terminal fitment of a single kind is often used in common for connection conductors difference in diameter in order to meet a demand of a user of an electric component unit and/or in view of a design of the unit. However, in each of the conventional terminal fitments, a distance between the distal ends of the holding elements in each pair opposite to each other is determined depending on a diameter of a connection conductor which is intended to be inserted through the terminal fitment. Thus, when a connection conductor which has a diameter increased as compared with predetermined one is inserted into the terminal fitment, an operator highly tends to have a sense of incompatibility due to a difference in force required for the insertion; thus, the operator often regards the connection conductor inserted and/or the terminal fitment as defective although they are actually non-defective, leading to a deterioration in yields. The connection conductor and/or terminal fitment regarded as defective would be reinspected by means of X-rays or the like, however, this leads to an extensive deterioration in operational efficiency.
Moreover, the conventional terminal fitments each cause a problem that application of force of pivotally moving a connection conductor about its central line to the connection conductor after insertion thereof through the terminal fitment causes the connection conductor to be cut by an edge of the distal end of each of the holding elements.